Process for purifying dielectric liquids



] Patented Oct. 27,, 1931 n ncniymn enenx vornosnmonr, rnnnsYLvenm ssIGNoR TO THE Sa nas nELAwAREfJ 1 a a a; Drawing.

r My invention is animproved method of purifying and rehabilitating liquids,-such as oil, used as dielectrics surrounding the con tact members of circuit breakers,switches and the like. The arcing incident to the operavtion of such circuit-breakers and switches, particularlyzonhigh tension lines, results'in the formation of, and the contamination "of the-dielectric by, minute dispersed particles oficarbon and other impurities, andin the'decomposition=oflconstituents of the insulating oil, with resultant lowering of its resistance 0 emulsification with waterintroduced there ,4 infby condensation of atmospheric moisture i-froni the air drawn in when the apparatus ,"breathes,or otherwise. These impurities foausea dangerous'reduction 'inthe dielectric,

strength of the oil and the effectiveness thereofas an arc quenching medium.,-and the wa 'ter of condensation or other moisture introduced into the casing remains suspended more or less permanently inthefoil, instead ofset- V tling readily therefrom to the bottom of the t casing below the electrodes, where its capacityfor harm is minimized. v I

I have discovered that by first removing "from the contaminated 'oil' the carbonaceous impurities,and preferably thesensible moisture, or the bulk thereof, thereaction or decomposition productsresulting from arcing V and tending topromote emulsificati'on may be readily extracted by adsorption and the oil purified" and its original properties restored t rapidly and without waste. If desired, the oil to'be treated may be subjected to a prelimremoval of free water. j

' The carbonaceouscontaminating particles suspended in the oil are so finely divided that they are normally notsusceptible, while dispersed in the oil, to the action of centrifugal force, or of subsidence orfiltration through 'inary drying, as bycentrifugation, for the usual filter media, such as cloth, and when concentrated by filtration through blotter fil- I ters as commonly practiced they form afilm or iayer almost impervious tothe' passage ofliquidtherethrough', andnecessitating for filter-' ing operations the use of. pressures so high as to risk disrupting the filter sheets; Moreover, the carbonaceous particles have an afiinity for relied upon to effect separation.

' 'rRooEssroRrURIrYING DIELECTRIC LIQUIDS s asms filedlmarch 5, 1925. s rial myia sra clarifying media so much greater than have the'emulsifying agents that the latter cannot be adsorbed in the presence of theformer without the use'ofan excessiveamount of clarifier, with a resultant excessive loss of oil and unnecessary cost.

In effecting the removal ofthe suspended carbonaceous particles and sensible moisture, Ii prefer to add to the contaminated oil a clarifier or substance such asdiatomaceous earth, fullers earth, or the like, with which theparticles of suspended matter or moisture will mechanically combine, as by enmeshment, adsorption or adhesion. A very small percentageof such clarifier is sufiicient to render porous the film formed by the pre oipitated carbonaceous particles if theoil 'is filter pressed,'with aresultant greatly increased output'from the press; tostratify the suspended'particles if the oil is centrifuged; or to carry down the particles ifsubsidence is '1 SPECIALTY :GOMIANIfQF rHI An rHI PENNSYLVANIA A CORPORATION on r The 'oil freed "from its susp n impuri I ties is treated with'an adsorptive material for the removal of the reaction products tending to promote emulsification, and which, due to their-lesser afiinities for adsorptive material than is possessed. bythe carbon and water, cannot be adsorbed While the latter are present in substantial'quantities Without the use ofusuch a large amount of adsorptive material as results in wastage of a large part of the oil. ,7 I have further found that the'carbon with which the oilis contaminated is positively charged, and that if a negatively charged media'isaddedto the oil the carbon will combine therewith completely and permanently, sothat it is unnecessary to employ a filter media having a mesh or pores impervious to carbonparticles as the carbon bearing substance may-be eliminated by the use of a usual filter cloth. As an example of the practical application of my'invention, there was added to dielectric oil, badly contaminated by circuit breaker use, one quarter ofone percentby Weight'of three times as fast as the rate of passage of 7 oil without the clarifier, To the clarified a oil, from whichthe carbon and sensible'moise 1 ture had been removed,"there wasadded one quarter of one percentiby Weight of finely divided'fullers earthyandithe product was again pfilter pressed for the removal of the fulleris earth and its adsorbed decomposi-: v tion product's tending to promote emulsifi cai Li The oils trea dri lof,s ti fac ryv "dielectric" strength, andhad a greaterresistance to. emulsification, thanjnew oil the same grade {and tests showed c'apaclty-oii the product, for service equal ,;to thatflobtained fromjnew oil. 7

' In another; demonstra i n f. P1 1 there was addedgto-gdielectric oil,-badly,con-1 taminatedwith carbon as a result of exposure to, agrcing,;; negfatively charged s'hreddedhlot- $61 filten' paper or pulp; The carbon was adsorbed bythepaper to Whichitpermanent- V 1y jadhereiqandthe shredded blotting paper wasthenfiltered iout-cbytheluse ofj'filter cloth;

clarifiedgoil as-:thentreated, for? the removal of decomposition products promotingemu'lsificati0n, gbylthe Iaddition itheretoof e adsorptive material suchas 'fullerls' earth-or V pulverized silica; gel and: its? elimination by filter pressing, centrifuging lor subsidencei iByrmygprocess I am enabledto render fit forljreuse large volumes 10f contaminated oil 1 the use of minute quantities of inexpens i'rerr'eagents or clarifiers to greatly increase the capacitywof the apparatus used; to avoid ifirequent chan ges or "rupturing of the'filter media, .and-eto produce a superior product. Having described myiinyention, I claim: '1. 'Thelprocess for preparing forquse as a f dielectric, roilcontaminated .duringuuse fials a the oil ilrdivided 'formflcarbon-adherent adsorptive :e'arth dielectric; by carbonaceous particles and soluble products ofrlecomposition tending to promote .emulsification, comprising removing such @panticles fromthe oil by. adding .to

material, and then E'separately adsorbing, in

inatheroil I 4 v. v v V V 2. Theprocess for preparing for use as a dielectricy-oilcontaminatedduring useas a dielectric by suspended Water, carbonaceous particles and solublefproducts ofdeco1'npositi' c{ -nftending{to promote emulsification, com: prising removing such particles and Water fromthe oiliby adding Watereabsorbing carbonaa'dherent' materialin'divided form to the oil, thenjseparatel'y adsorbing from the oil in adsorbent earth the decomposition products ;,f'. n.-, h ldielectric, o l contaminated during useas' a "The PrOQQ Sj r p ep ingfor. use as a r dielectric'by carbonaceousparticles and solublefproducts of. decomposition tending to s p a bly byprecipitationvof said particles, filteriifg dielectric, an, contaminated" durinj 'g-:,use as the decomposition products 7 herent'solid material to the oil, remo-ying from'the-oil the added solids With adhering adsorbing the decomposition products in adsorptive earth. i e I V x 4:. Thefprocessfor preparingf or 'useas a ti tending epr m te eml lsifiq tip iwmp s ngddi gwe il-fin yd v de that render p ervious: the" otherwise imperv'io ujs layer of solids formed'by precipitation of said particlesfifiltering the carbon par tides and d d so s r- '--'t lioil ;f en

adsorbing the decompositionp'rod? e s in; ed orp ve earths 1 f 15. The process, ring for, use ass dielectric, oil contaminated by carbonaceous particlesand solubleproducts of:decomposition tendin'g to promote emulsifioation, comprising adding to the oil finelydivided water ab r n d -tha render: r vi'ous the O h is mperv ous y f sol d io ed, the ar n Particles nii -adi e jiseli ffr' m th henp ab y'zad b ngi h eq re sition; products iniadsorptiyeearth.

fdQTl e process for; preparing:forusefas dielectr promote j emulsification, comprising adding carbon and absorbed-watn-ithen separately 91 3. c rb n u r rt 21 fe i 0 3" V uble I products oi decomposition tending to in divided form, afcarbongadher ent material to {the oil, then filtering wout saidi material with adheringf carbon, theni adsorbing emul- 7. i The process for preparing for ;use-as a dielectric, oil contamlnated with Water and i'fy 'n imP tns n' t ei in ad or n by the formation therein of solid, particles and soluble products f decomposition" durlnq use'a's adielectric,.comprisingradding to the oil ater-absorbent solid material "capable ofcombining mechanically With'the solid particles renioying the: added solids with absorbed-water and mechanically combined solid impurities, 1 then adsorbingthe iii-decomposition in" th'eioil. I I 1 8, The -pro'c'essifor preparing for, use as a oil in adsorbent earth the soluble products 'soluble} emulsion-promoting impurities," v V .;9. .Theprocessfon preparing for use as a dielectric, oil. contaminated by V suspended o 7 7 finelydivided solid particlesllandf withisoh promote; emuls ficatlon, compr sing addnng in, I

1 10 9 -i li d sten ing o; p o otex mulifi'een, geempri ing addi g t lily:v to l dielectric, oil contaminated by {carbonaceous V divided form a carbon-adherent solid having an electric charge opposite to that ofthe suspended selid particles in the il,'rem0ving from the oilthe added solid andadhering solid particles, then adsorbing from the oil in adsorptiveearth the soluble emulsion-promoting impurities.

Signed at Philadelphia, in the county of Philadelphia, and State of Pennsylvania,

this 2nd day of March, 1925.

LEE HINCHMAN CLARK. 

